Washington DC, the Current Best Restaurants
A lot of these places are not open for dinner on Sunday nights...
I would add Blue Duck Tavern to the list - I was there on a Sunday night and had an excellent meal. Highlights were the pork belly and braised beef shortribs.
Also, another restaurant which I don't think would quite make the "best" list, but I consider very very good, is PS7s. Delicious food and creative drinks too.